Gas fume problem halts Metro work for 3 months Delay may add $16 million to cost

October 07, 1992|By Peter Jensen | Peter Jensen,Staff Writer

Leaking gasoline fumes have led to a three-month halt in excavation of a Metro tunnel, contributing to a potential $16 million cost overrun on the subway extension that has been dogged by expensive encounters with petroleum-tainted soil in East Baltimore.

Mass Transit Administration officials said the stoppage was necessary because compressed air used to keep out ground water has been escaping from the tunnel, causing gasoline fumes to surface from contaminated soil in the Jonestown neighborhood.

The three-month delay will give workers time to pour a concrete lining in a portion of a tunnel that runs west from the Johns Hopkins Hospital to a point underneath East Baltimore Street, about 600 feet east of the Shot Tower.

Problems with underground gasoline at various excavation points in East Baltimore have been a perennial obstacle for the subway project, which began in 1990.

Officials claim it is a principal reason why the 1.5-mile extension from Charles Center to Hopkins may come in as much as $16 million -- or 5 percent -- over the original $321 million budget when the line is completed in late 1994 or early 1995.

"We don't really know what our costs are until it's all finished, but the problem [with gasoline] has dramatically affected our costs," said Peter J. Schmidt, the MTA's assistant general manager for development. "The difficulties on this job always seem to come back to gasoline."

The subway's worst brush with gasoline came in late 1990, when tunneling had to be delayed 10 months when crews ran into gasoline-saturated soil and experienced some machinery problems.That added $20 million to the cost of construction, in part because the MTA was forced to make the tunnel explosion-proof.

"We're dealing with a very old, historical problem," said Michael Sullivan, spokesman for the state Department of the Environment. "We don't find [liquid] gasoline. We find vapors that could be a problem that dates back 50 or 60 years."

Workers have removed from the Jonestown area 10 underground tanks that formerly held heating oil, including four in a vacant lot at East Baltimore and North Exeter streets, since fumes were detected last month.

Mr. Sullivan said the escaping fumes do not pose a health or safety hazard because noxious hydrocarbons are in relatively low concentrations. Residents in a two-block area have complained that the smell is most pronounced in their basements, where investigators reported that airborne hydrocarbon levels average between five and 10 parts per million.

Gasoline can be smelled at about five parts per million, according to experts.

The problem is expected to add only two to three extra weeks to the schedule for construction of the Metro extension. It affects only the inbound, or more northerly of the twin subway tunnels, and excavators can work on two sections of the out bound tunnel while the lining is installed.

Nevertheless, the gas fumes could worsen when the parallel outbound tunnel -- which is also being dug east to west -- reaches the same point in the neighborhood in a matter of weeks.

Officials hope the ventilation system along East Baltimore Street will have corrected the problem by then, however.

The fumes surfaced in Jonestown two weeks ago, and led to the evacuation of the Jonestown Day Care Center, which caters to low-income families. The non-profit center and its 120 children, who range in age from 2 to 12, have been temporarily relocated to the sixth floor of the Brokerage Building near the Inner Harbor.

The MTA declined to estimate the costs of this most recent incident, but so far the agency is picking up all the bills, including the cost of the day-care center's relocation. More than 100 monitoring wells and vent pipes have been installed in the neighborhood to help dissipate the fumes.

Ideally, any property owner responsible for a leaking tank would be billed, but investigators fear that the problem is too diffuse to establish a culprit.

They have not been able to determine which of the underground tanks were leaking.